Conventional orthogonal frequency division multiplexing (OFDM) networks and orthogonal frequency division multiple access (OFDMA) network are able to improve the reliability of the channel by spreading and/or coding data traffic and control signals over multiple subcarriers (i.e., tones). However, if the channel is flat, frequency diversity cannot be achieved. In order to overcome this, it is possible to introduce artificial frequency diversity into the transmitted signal. A technique for artificially introducing frequency diversity into an OFDM environment was disclosed in U.S. patent application Ser. No. 11/327,799, filed on Jan. 6, 2006 and incorporated by reference above. In the device disclosed in Ser. No. 11/327,799, multiple copies of the same OFDM symbol are delayed by different delay values, then amplified by the same or different gain values, and then transmitted from different antennas. This artificially introduces frequency-selective fading in the ODFM channel, thereby allowing frequency selectivity to be exploited using frequency-domain scheduling for low-to-medium speed mobile devices or frequency diversity for higher speed mobile devices.
However, when selecting the symbol processing parameters (i.e., delay values and the gain values) applied to the OFDM symbols, it is important to take into consideration the user channel type and the mobile speed. To accomplish this, channel estimation is performed and the symbol processing parameters are determined based on the channel estimates and mobile speed. Therefore, there is a need for improved apparatuses and methods for performing channel estimation in an OFDM wireless network that artificially introduces frequency diversity by delaying and amplifying multiple copies of the same OFDM symbol and then transmitting the delayed and amplified OFDM symbols from different transmit antennas.